Calibre doubling content

After recent upgrade, Calibre started doubling content of the book.
Here is one example (a free Gutenberg's book):
original epub: Attachment 102664
converted epub:Attachment 102665
log: Attachment 102667

Checking "do not split on page breaks" somewhat resolves this problem, but I guess, it's not quite right. Previous versions didn't do that.

Hope, this problem can be fixed soon.

Sorry for my English. I'm not a native speaker.

Attached Files

	pg42277.epub (152.2 KB)
	The Grizzly _ Our Greatest Wild Animal - Enos A. Mills.epub (794.8 KB)
	log.txt (10.7 KB)